The invention relates to a drive arrangement for the drive elements for threading the upper thread into the eye of the needle of a sewing machine.
Drive arrangements for threading devices of this type are known in many embodiments. They serve to relieve the operator of the sewing machine from the tedious threading of the upper thread into the eye of the needle. Simple threading aids are operated manually, i.e. the upper thread is inserted into a suitable tool and this facilitates the treading process. In automatic threading devices first the thread must be placed in front of the device before the latter then performs the threading process via separate drives in the sewing machine.
The most frequently used automatic threading devices pivot the threader around a horizontal axis downwards from a resting position in the upper arm towards the needle. Further, motorized threading devices are also known in which, similar to the manually operated ones, the threading device is guided vertically downwards along an actuator rod parallel to the needle rod and is pivoted out of this position around said actuator rod. These known threading devices require a suitable electric drive for the lowering process, e.g., a stepper motor, which guides the threading device via a toothed rod downwards and, after the threading, back upwards. Here, the pivoting motion inevitably occurs in a curved path, along which the device at the end of the lowering motion is additionally rotated around the actuator rod.
Both the threading devices with motion around the horizontal axis in the upper arm of the sewing machine as well as those that are vertically displaced by an electric motor need comparatively much space. This leads to a voluminous upper arm housing, which limits the direct visual contact of the operator to the sewing area.